What is the ACA? (back to top)

The American Cryptogram Association (ACA) is a non-profit organization dedicated to promoting the hobby and art of cryptanalysis — that is, learning to break ciphers. Another good description of our hobby: “Recreational Cryptanalysis,” which expresses both its fun and serious sides.

The ciphers published in The Cryptogram (Cm) are contributed by ACA members for the enjoyment of all of us. Some messages are educational, some are humorous, and some are intentionally crafted to be more difficult to solve.

ACA ciphers are challenging, but the skills to solve them can be learned by anyone. Different ciphers require learning different solving skills, which is like learning different exercises, but they are exercises for your brain.

Why should I join the ACA?(back to top)

Since I can find cryptograms to solve for free, why should I join the ACA?

Membership in the ACA is special in a number of ways.

The ACA has a long history, rooted in member cooperation for learning cryptanalysis skills.  The ACA formed in 1929, and the first issue of The Cryptogram was published in 1932.

We are an all-volunteer, non-profit organization.  Officers and editorial staff alike all love solving ciphers.  The motive behind each issue of Cm is to provide an excellent set of ciphers for our members to solve.

Member interaction.  Other members are willing to answer questions or give help when you are learning a new cipher type or get stuck.  We help you gain the skills you need to solve.

Good variety of cryptograms — written & submitted by a large number of members.  Members get to see their own ciphers published, too!

Good variety of cipher types — over sixty different types of cipher.  Simple substitution, polyalphabetic substitution, periodic ciphers, route transposition ciphers, Morse-based ciphers, Fractionated ciphers, digraphic ciphers, cryptarithms, and even headline puzzles.  See the cipher types from The ACA and You.

Having a variety of cipher types is more challenging, mentally stimulating, and satisfying than just simple cryptograms.  Some ciphers require 5 minutes, some 5 hours, some 5 days.  When learning a new type, our archive provides lots of examples on which to practice (with solutions).

We are passionate about solving, and we would love to share our hobby with you. Check out our Sample Issue of The Cryptogram to see examples of multiple cipher types, including an ornamental cipher on its cover, and tutorial solutions to all of its challenge ciphers. If you have questions about the sample issue, please write to nudge <at> cryptogram <dot> org.

What is Cm?(back to top)

The bi-monthly journal of the ACA is titled The Cryptogram, and it is affectionately abbreviated as Cm.

How do I sign in to the Members area of the ACA Website?(back to top)

When you click the “Members” tab on the ACA website, www.cryptogram.org, you will see several choices including “Downloads” and “Digital Cons.” When you click on one of these, you are presented with a page that says something like “This content is restricted to ACA members …”. At the bottom of this page you will find “Existing Users Log In” which asks for username and password. The username is “aca” and the password is found on page 11 in the current issue of The Cryptogram (Cm). After successful authentication you will be able to access the information in the Members area.

What is Sample Cm?(back to top)

We offer a free, abbreviated sample issue of Cm so others can get an idea of the ciphers we utilize. It introduces a handful of cipher types, gives challenge ciphers in those types, and we also offer tutorial solutions that demonstrate, step by step, a solution to each of the challenge ciphers. The cipher types covered are intended to be some that are more easily described to a non-member. The Sample Cm page is available online on the ACA website under Resources.

How do I contact the Treasurer?(back to top)

The Treasurer is the main contact for all financial and membership matters: payments, subscriptions, renewals, nom requests and address changes. The Treasurer’s contact information is available on the ACA website under Contact Us.

What are the ACA membership dues?(back to top)

The current membership costs are listed on the ACA membership form that is referenced on the Become A Member Page.

To whom do I send my membership dues?(back to top)

Dues should be sent the ACA Treasurer. Sending them to any other officer might delay your membership.

Note: payments must be in U.S. dollars via a check drawn on a U.S. bank, unless other arrangements are made with the treasurer in advance.

May I use PayPal to pay for my membership?(back to top)

Yes, you may now use PayPal for paying membership costs! Please see our Membership page for details.

What is a nom?(back to top)

In the ACA a nom is a pen name (as in “nom de plume”) or code name which provides a concise and informal way to refer to an ACA member. Your nom will appear in Cm to identify you in the Solvers List, as the contributor of a cipher, etc. A nom is not mandatory — if you have not selected a nom, your last name and first initial are used.

A nom is also an example of how ACA members relate to each other on equal terms. Using the nom eliminates choosing how to correctly address another member in an email or message: Mr., Mrs., Dr., Ms., Miss, Prof., Special Agent, The Honorable, etc. A nom is the simple way to address any of our fellow members.

See Cm or the ACA Directory for examples of member noms. They might be anagrams, sobriquets earned over the years, something of special meaning, or simply whimsical.


(Updated: October 2018)